Lubricant



, adhesive and coherent.

Patented Nov. 30,

UNITEDSTATES PATENT LUBRIC 2' Lloyd L. Davis and Bert H. Lincoln, Ponca City,

Okla" assign on, by means assignments, to Socony-Vacnum Oil Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application March21,1938,

. Serial No. 197,195

.3 Claims. 252-32) Our inventionrelates tolubricants and more particularly to 'a high quality lubricant containing special soaps.

Modern design in'internal combustion engines, and more particularly in Diesel engines, has imposed severe demands on lubricants. In order to properly lubricate modern Diesel engines, the

lubricants must be able to maintain a lubricating film at greatly increased loads and at considerably ,higher temperatures of operation." The severe conditionsof use reguire the lubricants to be more stable than those known to the art. Failure to provide a proper lubricant with modern Diesel engines results in operating difficulties. These demands on lubricants are occasioned, too, by other internal combustion engines though not to the same extent as by .Dieselenginesh f The failure to supply proper lubricants is evidenced by so-called sludge formation; resultins in sticking piston rings and similar troubles.

By sludge we meaniprecipitants and, matter formed during the operation of the internal combustion engine, which interfere with properlubrication. Some sludges are hard. Others are Still other sludges are soft and pliable and easily disintegrated.=

Probably the most damaging aspect of 013360:

tionable sludge results in piston rings sticking. This in turn causes not only increased cylinder wear but frequently scoring of the cylinder walls and sometimes, in severe cases, an actual seizure of the piston by the cylinder walls, due to fusion of metal.

The difliculties which must be overcome cannot be surmounted by changing the character of the hydrocarbon oil, per se. Mineral lubricating oils are peculiarly susceptible tooxidation and sludge formation.

It has been suggested to improve hydrocarbon oils by adding thereto halogenated metallic soaps. Another suggestion to overcome the difficulties mentioned has been toadd to hydrocarbon oils small amounts of aromatic substituted stearic acid soaps of calcium. The resulting compositions of matter formed by the hydrocarbon oil and these addition agents have been found .to be inadequate. Neither halogenated metallic soaps or calcium soaps of aromatic substituted stearic acid are sufficiently soluble in bydrocarbon oils to give a solution suficiently stable under severe operating conditions of use. In order to overcome the solubility dimculty, free fatty acid or free substituted acids have been blended therewith to increase their solubility in hydrocarbon oils. While free acidity helps solubility, it contributes to corrosiveness in the finished lubricant and it has been found that,

in the commercial manufacturing and distribution of these lubricants. The defective solubility characteristics of the agents o'fthe prior art is critical and lubricants in which-they are used cannot be fortified with a sufiicient amount of the addition agents now available to enable the resulting composition to perform its normal duties.

When abnormally heavy duties are imposed upon such lubricants, even for short periods of time, sludging occurs, resulting in piston ring sticking and increased cylinder wear.

One object of our invention is to provide addition agents for lubricating oil which will greatly i reduce or eliminate ring sticking and which are sufiiciently solublein lubricating oils, including Pennsylvania base oils, solvent treated oils and high viscosity oils, to be effective.

A further object of our invention is to provide I a lubricating composition which will substantially reduce or substantially eliminate ring sticking in all internal combustion engines, in-

cluding airplane enginesjautomobile engines, and.

heavy duty internalcombustion engines, particularly those of the Diesel type.

Another object of our invention isitoi provide a lubricant comprising a hydrocarbon oilyand an addition agent which is sufliciently soliible in the mineral oils, thereby avoiding un ase of acidic solubility agents.

Another object of our invention is to provide a, lubricant containing an addition agent,-prci viding increased fllm strength, in which the resulting composition is substantially non-corrosive.

Another object of our invention is to provide a lubricant containing an addition agent in which objectionable adhesive sludge formation is minimized.

Another object of our invention is to provide a lubricant containing an addition agent which will convert such sludge as may be formed from mineral oil changes in use into soft, pliable, nonadherent sludge which is unobjectionable.

In general, our invention contemplates the addition of relatively small-amounts of special soaps to hydrocarbon lubricating oils.

The particular special soaps used in our invention are made from acids of four types, namely;

a. Acids resulting from the oxidation of petroleum wax or high molecular weight petroleum hydrocarbons.

b. Acids resulting from the oxidation of petroleum wax or high molecular weight petroleum hydrocarbons in which one or more aromatic,

aryl, or closed chain radicals have been attached thereto.

c. High molecular weight fatty acids to which are attached one or more aliphatic, alkyl, or open chain radicals.

d. Aromatic or aryl closed chain acids to which are attached one or more long chain aliphatic,

alkyl, or open chain radicals.

The inorganic compound to be reacted with. the foregoing acids in order to form our special soaps includes the metals, oxides, hydroxides, or salts of! Calcium Cadmium Barium Boron Strontium Antimony Magnesium Chromium Aluminum Cobalt Tin Manganese Zinc. I

. assaccr petroleum hydrocarbon, as for example, a parailin wax or high molecular weight hydrocarbon oils such as petrolatum or bright stock. These hydrocarbons may be oxidized by any of the methods known to the art, by oxygen containing air, gaseous oxygen, or chemical oxidizing agents. The crude oxidation products are separated into acid reacting and non-acid reacting components to obtain the acids suitable for use in compounding the soaps employed in our compositions .of matter. I 1

The exact chemical composition of the acids resulting from the oxidation of petroleum hydrocarbons is not known and varies over wide limits,

depending upon the particular type of petroleum hydrocarbon subjected to oxidation.

By way oi example, a petroleum wax having a melting point of 124--126 F. was oxidized and acids recovered by precipitating them as insoluble soaps, followed by hydrolysis, to obtain the acids. For convenience, these acids will be termed "wax acids." Calcium soaps, aluminum soaps, zinc soaps, and magnesium soaps of these Aluminum-wax acid soaps plus 99.75% SAE wax acids were formed and the following compositions of matter confected:

Calcium-wax acid soaps plus 99.50% SAE 30 mineral oil Calcium-wax acid soaps-plus 99.00% SAE 40 min- I eral oil Calcium-wax acid soaps plus 98.00% SAE 20 mineral oil Magnesium-wax acid soaps plus 99.00% SAE 30 mg or fluxing material, thus preventing the deposition of sludge-like materials which cause ring sticking.

d. They act to keep sludge-like materials formed in a soft, pliable, non-coherent, and nonadherent condition. (This property results from som mechanism which is not clear .to us but is probably related to the molecular size of the materials.)

-e. They are relatively non-corrosive at high temperatures.

f. If, under abnormally severe conditions, some slight decomposition takes place, the decomposi tion products are only weakly acid or alkaline and chemically inactive.

(a) Organic acids of type a, above listed, are normally made by the oxidation of a high boiling mineral oil 1 Magnesium-wax acid soaps plus 98.00% SAE 30 mineral oil Magnesium-wax acid soaps plus 96.00% SAE 30 mineral oil All of the foregoing compositions were oi a viscosity only slightly greater than the viscosity of the base mineral oil. All of them were fluid lubricants, that is, none were of the solid or semisolid grease constituency. Each of the compositions of matter was tested and found satisfactory for accomplishing theobjects of our invention.

(11) Petroleum acids (by this is meant acids recovered from the oxidation of hydrocarbon oils) were chlorinated and then subjected to Friedel- Crafts condensations with benzene, naphthalene, and diphenyl to obtain petroleum acids having substituted aromatics, aryl, or closed chain radicals the eon.

The petroleum acid is chlorinated to any desired extent to obtain monochlor, dichlor, trichlor, or polychlor petroleum acids. These chlorinated petroleum acids may be reacted with aromatic compounds as above described.

For example, monoand. trichlor petroleum acids were respectively reacted with approximately one and three molecular equivalents of member the following closed chain radicals to obtain vari= ous substituted petroleum acids;

Benzene,

Xylene.

Naphthalene, i

Anthracene,

Benzene with one hydrogen substituted with a radical obtained from chlorinating 124 i i-126 F. melting point wax,

Naphthalene with onehydrogen substituted with three radicals obtained from chlorinating 124 F.-l26 F. melting point wax,

Cyclohexane,

Diphenyl,

Ethyl cyclohexane,

Octadecal cyclohexane,

Ethyl diphenyl,

Di-ethyl diphenyl,

Octadecal diphenyl,

Di-octadecyl diphenyl,

Diphenyl ether,

Ethyl diphenyl ether,

Lauryl diphenyl ether,

Benzophenone,

Dibutyl benzophenone,

Triphenyl benzoi,

Ethyl benzoate,

Lauryl benzoate,

Furfural,

Methyl furfural,

Methyl phenyl pyrrole.

The above substituted petroleum acids were converted into various soaps as follows:

' Calcium-monophenyl petroleum acid soap,

Aluminum-mononaphthyl petroleum acid soap, Strontlum-anthranyl petroleum acid soap, Tin-di-phenyl substituted petroleumacid soap, Zinc-octadecyl cyclohexane substituted petroleum acid soap, Barium-di-octadecyl troleum acid soap,

diphenyl substituted pej Calcium-benzophenone substituted petroleum acid soap,

, Aluminum-triphenyl benzol substituted petroleum Lubricants were prepared by adding 1.5% of each of the above soaps to 98.5% of a hydrocarbon oil having an SAE viscosity of 30. It was found that metal soaps of aromaticsubstituted petroleum acids accomplish the objects of our invention and are suitable as addition agents to hydrocarbon oils to minimize piston ring stick- 7 ing.

(a) The organic acids may be easily prepared by substituting one or more large petroleum hydrocarbon molecules on the various fatty acids and the resulting product converted into the various soaps, I

Petroleum is a mixture of hydrocarbons of varying molecular weight; but by selecting a comparatively close boiling range material, it is possible to minimize the numberof diiierent hydrocarbon molecules in the out. To accomplish the objectives of this invention, it is not necessary Whatever fraction of crude petroleum that is see lected will prove satisfactory, but it is desirable to select a fraction having a boiling point above about -F'. The various fatty'acidsmay be used; but if a low molecular weight fatty acid is used, then at least one high molecular weight petroleum hydrocarbon should be attached to it, or two or more of the lower molecular weight petroleum hydrocarbons should be attached to it.

For example, with acetic acid a petroleum hydrocarbon of the wax boiling range should be I employed or two hydrocarbons of the kerosene boiling range. With stearic acid one or more of the high or low boiling range, or high or low molecular weight, petroleum hydrocarbons may be v employed.

Some of the normal fatty acids which may be employed herein are acetic, propionic, butyrlc, capric, lauric, palmitic, stearic, caranaubic, melis sic. oleic, linoleic, ricinoleic, and the like.

To the foregoing fatty acids may be attached one or more aliphatic hydrocarbons of from six to fifty carbon atoms. The cheapest source of these hydrocarbons is petroleum oil; therefore hydrocarbons or fractions of comparatively narrow boiling range from the gasoline, kerosene, gas oil, lubricating oil or wax boiling range may be employed. Obviously hydrocarbons similar to those from petroleum may be employed regardless of source, or pure synthetic hydrocarbons may be employed. By aliphatic hydrocarbons we include the hydrocarbons obtainable from petroleum oil regardless of the source.

This invention is not limited to the method of combining the fatty acids and the aliphatic hydrocarbons since any of the well known methods of addition or substitution may be employed. Stearic acid with one, two, and four substituents from a wax having a melting point of 124- 126' F. was formed and converted into various soaps. Oleic acid, with as many as six substituents from a, hydrocarbon boiling within the gasoline boiling rangewere formed andconverted into various soaps,

A number of aliphatic substituted fatty acids were formed, as for example:

Calcium-stearic-monowax hydrocarbon soap, Calcium-stearic-diwax hydrocarbon soap, Calcium-st'earic-triwax hydrocarbon soap, Calcium-stearic-tetrawax hydrocarbon soap,

Aluminum-oleic-monokerosene hydrocarbon soap, ,Aluminum-oleic dikerosene hydrocarbon soap,

.Tin-caranaubic-digasoline hydrocarbon soap,

Tin-caranaubio trigasoline hydrocarbon soap,

Tin-caranaubic tetragasoline hydrocarbon soap.

Compositions of matter were compounded containing 98.5% of an SAE 20 hydrocarbon oil and 1.5% of metal soaps of aliphatic substituted fatty acids and these were found ,to accomplish the objects of our invention.

(d) The organic acids of class d above, are prepared from aromatic or closed chain acids with one or more high molecular weight substituents such as wax hydrocarbon substituents on an aromatic nucleus. Some of the ring or closed chain acids which are satisfactory for the introduction of a high molecular weight substituent are:

One or more aliphatic or open chain radicals may be attached to these ring acids. The aliphatic radical may contain from four to fifty carbon atoms. 'Any of the petroleum hydrocarbons having the requisite number of carbon atoms may be employed.

The aliphatic hydrocarbon radicals may be introduced into the ring compound by any of the 3 well known methods such as by the Frledel-Crafts reaction or one of its modifications. If the Friedel-Crafts reaction is employed to introduce the open chain radical into the closed acid chain, then either one, two, three or more halogens may be introduced into the aliphatic radical, depending on whether the mono-, di-, or tri-substitution product is desired.

A number of aliphatic substituted ring acids were formed and converted into soaps as follows:

Calcium-benzoic-monowax hydrocarbon soap Calcium-benzoic-diwax hydrocarbon soap Calcium-benzoic-triwax hydrocarbon soap Aluminum-phenylacetic-monokerosene hydrocarbon soap Aluminum-phenylacetic-dikerosene hydrocarbon soap Aluminum-phenylacetic-trikerosene hydrocarbon soap Zinc-phthalic acid-monogasoline hydrocarbon soap Zinc-phthalic acid-digasoline hydrocarbon soap Zinc-phthalic acid-triga'soline hydrocarbon soap Zinc-phthalic acid-monowax hydrocarbon soap Calcium-phthalic acid-monowax hydrocarbon soap Calcium-phthalic acid-monokerosene hydrocarbon soap Aluminum-phthalic acid-monowax hydrocarbon soap Aluminum-phthalic acid-monokerosene hydrocarbon soap metal soaps were added to 98.5'percent of an SAE .30 mineral oil and were found to accomplish the objects of our invention.

It is to be understood that the examples above given are by way of illustration only'and not by way of limitation and that any soaps of the following group are of use in our invention:

Metal soaps of petroleum acids Metal soaps of substituted petroleum acids Metal soaps of aliphatic substituted fatty acids Metal soaps of aliphatic substituted aromatic acids.

It will be observed that, broadly stated, our invention comprises the addition to a hydrocarbon oil of small amounts of metal soaps of acids selected from the. following group:

a. Petroleum acids (that is, acids obtained by the oxidation of petroleum hydrocarbons) b. Substituted petroleum acids c. Aliphatic substituted organic acids 1. Fatty acids 2. Aromatic acids The amount of soaps to be used varies over wide limits. The smallest amount which might be used practically is about one fourth of one percent. The highest concentration of the addition agent would not be more than fifteen percent. A

preferential range for practice would be between ton ring sticking difliculties by causing such sludge as is formed to be of the soft, non-adherent character.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, what we claim is:

1. A'lubricant comprising in combination a hydrocarbon oil and from one fourth of one percent Compositions of matter were formed in which 1.5 percentof the aliphatic substituted ring acid to fifteen percent by weight of a metal soap of an aliphatic substituted fatty acid. 1

2. A lubricant comprising in combination a hy- 

